Who would have thought John Mayer would extend the legacy of the Grateful Dead past the 2015 Fare Thee Well 50th anniversary concerts?

Mayer, who played the last date of his The Search for Everything World Tour April 22 at Las Vegas’ T-Mobile Arena, has reunited with guitarist Bob Weir, drummer Bill Kreutzmann, and percussionist Mickey Hart to launch Dead & Company’s third tour on May 27 at MGM Grand Garden Arena. Bassist Phil Lesh remains the sole living member of the Grateful Dead to not participate, leaving intact the “Fare Thee Well” covenant between the five Dead alumni to never share the stage again. No one said the music was going to stop, however.

Mayer became a Deadhead after “Althea” from the band’s 1980 album Go to Heaven popped up on his Pandora playlist in 2011. Ever searching for ways to balance his pop star image with musical authenticity, Mayer rerouted his penchant for Clapton-style blues power into appreciating the guitar stylings of Weir and late Dead guitarist Jerry Garcia. He also found his vocal range well suited for songs such as “Sugaree,” “Mississippi Half-Step Uptown Toodeloo” and “Box of Rain.” In January 2015, while working on songs at Capitol Studios in L.A., he was invited by producer Don Was to attend a meeting with Hart and Weir. By March, after inviting Weir to jam together on the Late Late Show during an episode he guest hosted, he was playing in the band.

For some Deadheads, the thought of Mayer filling in for Garcia was blasphemous, and a few cried foul due to the perception of closure surrounding the Fare Thee Well shows. Still, the members have played together in various lineups since Garcia’s passing in 1995, 30 years after Lesh joined pre-Dead band The Warlocks on bass and a random perusal of a dictionary provided the name the Grateful Dead would ride to fame. Hart, who joined in 1967, teamed up with Lesh and Weir to form The Other Ones in 1998, with Kreutzmann getting on board in 2000. By 2003, they had changed their name to The Dead, which played its last show on July 4, 2009, at the Rothbury Music Festival in Michigan.

Hart and Kreutzmann also played with Phish bassist Mike Gordon in the Rhythm Devils, which ended its first tour in Las Vegas at the October 2006 Vegoose music festival. Gordon declined to join Dead & Company, leaving the door open to Allman Brothers’ bassist Oteil Burbridge to enter the picture. The participation of The Dead keyboardist Jeff Chimenti was a given, and Dead & Company made its debut in October 2015 with three sold-out concerts at Madison Square Garden.

This year’s summer tour takes the band to 15 different cities, with two sets of Grateful Dead music at each of the 20 concerts, from the Hollywood Bowl to Chicago’s Wrigley Field. Mayer more than lived up to the task of filling in for Garcia, but more importantly without his inspiration, initiative and total immersion into music he had never really listened to before 2011, there would be no Dead & Company. “We weren’t looking for John,” Hart says in the April issue of Relix magazine. “John came to us so impassioned that we couldn’t turn him down. It would be stupid.”

MGM Grand, 8 p.m. May 27, starting at $50 plus tax and fee. 800.745.3000 Ticketmaster